Synthesis of 1,2, and 9-methyl derivatives of 4,9-dihydro-6-methoxy-3-methyl-4-oxo-1H(2H)-pyrazolo[3,4-b]quinoline and 4,9-dihydro-6-hydroxy-3-methyl-4-oxo-1H(2H)-pyrazolo[3,4-b]quinoline and their antiviral activity

Abstract

The paper describes syntheses of 4,9-dihydro-6-methoxy-3-methyl-4-oxo-1H(2H)-pyrazolo[3,4-b]quinoline (Ia), its 1-methyl derivative (Ic), 1,9-dimethyl derivative (Ie), 2-methyl derivative (IIa), and 2,9-dimethyl derivative (IIc). Demethylation of these compounds with hydrobromic acid afforded 4,9-dihydro-6-hydroxy-3-methyl-4-oxo-1H(2H)-pyrazolo[3,4-b]quinoline (Ib), its 1-methyl derivative (Id), 1,9-dimethyl derivative (If), 2-methyl derivative (IIb), and 2,9-dimethyl derivative (IId) respectively. 4,9-Dihydro-6-hydroxy-3,9-dimethyl-4-oxo-1H-pyrazolo[3,4-b]quinoline (Ig) was prepared by demethylation of Ie and/or IIc with pyridine hydrochloride. The compounds prepared were tested for antiviral activity in vivo in mice against influenza virus A2-Hongkong and encephalomyocarditis virus.

1H-Pyrazolo[3,4-b]quinolines: Synthesis and Properties over 100 Years of Research

“…However, th are some diseases that must be cured by the use of antivirial drugs (e.g., HIV, herpes ruses, hepatitis). A huge family of 1H-pyrazolo [3,4-b]quinoline derivatves (Figure which were obtained by the method of Stein et al [29] and then functionalised, were s thesised and tested for antiviral activity by the group from the Research Institute for P macy and Biochemistry in Prague in the 1980s [194][195][196][197][198][199][200][201]. Anilino derivatives were tested against the A2-Hongkong virus and against the cephalomyocarditidis (EMC) virus in vivo in mice.…”

Synthesis of pyrazolopyridine and pyrazoloquinoline derivatives by one-pot, three-component reactions of arylglyoxals, 3-methyl-1-aryl-1H-pyrazol-5-amines and cyclic 1,3-dicarbonyl compounds in the presence of tetrapropylammonium bromide

“…The literature contains many examples of self-dual Leonard pairs. For instance (i) t ated with an irreducible module for the Terwilliger algebra of the hypercube (see [4, Co Leonard pair of Krawtchouk type (see [10, De nition 6.1]); (iii) the Leonard pair associa module for the Terwilliger algebra of a distance-regular graph that has a spin model in bra (see [1,Theorem], [3,Theorems 4.1, 5.5]); (iv) an appropriately normalized totally (see [11,Lemma 14.8]); (v) the Leonard pair consisting of any two of a modular Leona De nition 1.4]); (vi) the Leonard pair consisting of a pair of opposite generators for bra, acting on an evaluation module (see [5,Proposition 9.2]). The example (i) is a spe examples (iii), (iv) are special cases of (v).…”

“…The presence of pyrazoloquinoline moieties in numerous natural products makes them an important class of heterocyclic compounds with several biological and pharmacological activities, such as anti-mycobacterial [3], anti-microbial [4], antiviral [5]. Pyrazolopyridines have also received more attention because of their wide range of biological and pharmacological properties, such as anti-pyretic [6] and anxiolytic [7], antimalarial [8], and this has made such derivatives increasingly important.…”

Microwave assisted one-pot synthesis of pyrazoloquinazolinone derivatives and their application on printing of synthetic fabrics

“…Pyrazolo [1,5-c]quinazoline derivatives are very important heterocyclic compounds and have been widely used as antiviral agents (Radl and Zikan, 1987), antimicrobial agents (Vartale et al, 2006), optical brighteners (Gold, 1971), dyestuffs (Rangnekar and Puro, 1990;Tsai and Wang, 2005) and colorants (Gondek et al, 2007b) and in photoluminescence (Całus et al, 2007) and electroluminescence (Gondek et al, 2007a) studies.…”